Simplify the following expression: $r = \dfrac{6y - 7}{4y + 8} \div \dfrac{1}{3}$
Answer: Dividing by a number is the same as multiplying by its inverse. $r = \dfrac{6y - 7}{4y + 8} \times \dfrac{3}{1}$ When multiplying fractions, we multiply the numerators and the denominators. $r = \dfrac{(6y - 7) \times 3} {(4y + 8) \times 1}$ $r = \dfrac{18y - 21}{4y + 8}$